Umbrella base



FIG. 1 is a back, top, and right side perspective view of an umbrellabase embodying my new design.

FIG. 2 is a top view thereof.

FIG. 3 is a bottom view thereof.

FIG. 4 is a back view thereof.

FIG. 5 is a front view thereof.

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof.

The broken lines are shown for the purpose of indicating environmentalstructure and/or portions of the umbrella base and form no part of theclaimed design.

CLAIM The ornamental design for an umbrella base, as shown anddescribed.